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  • php sql纯语句

    条件语句CASE

    CASE
        WHEN a.business_mark !='' THEN 2
    END
        as source_type,

    条件语句 CASE ELSE

    CASE
            WHEN a.business_mark !='' THEN 2
            WHEN a.rebate_id !='' THEN 1
        ELSE 0
        END
            as source_type,
    CASE a.is_pay
            when 1 then 20
            when 2 then 10
        end as recharge_state,

    if语句 

    if(a.receive_time='',null,from_unixtime(a.receive_time)) as time_receive_user_pay,

    如果receive_time为空,则取第二个值,否则就去第三个值

    时间转化 (1477984283 转 Y-m-d H:i:s)

    from_unixtime(a.add_time) as time_publish_user_pay,

    字段长度截取 CAST(a.price*0.93 AS DECIMAL(18,2))  

    CASE
            when a.rebate_id !=' ' OR a.business_mark !=' ' THEN CAST(a.price*0.85 AS DECIMAL(18,2)) *100
        ELSE CAST(a.price*0.93 AS DECIMAL(18,2)) *100
        end as actual_pay_to_receiver_amount,

    子查询

    case 
            when a.business_mark !='' then (select id from dl_business where mark=a.business_mark)
            when a.rebate_id !='' then a.rebate_id
        end 
            as source_id,

    条件为空查询

    SELECT * FROM `dl_order` where business_mark is not null;
    SELECT * FROM `dl_order` where business_mark !='';


    SELECT * FROM `dl_order` where business_mark is null;

    select max(length(desc)) from table order by length desc

    两表查询

    select 
        a.member_id as user_id,
        a.game_level as division_id,
        a.add_time as time_create, 
    
        b.name as division_name
        
    
    from dl_member_attest a
        left JOIN dl_game_type b ON a.game_level = b.id
    limit 0,10

    三表查询

    SELECT 
        a.id as user_id,
        c.id as division_id,
        c.name as division_name,
        a.member_mark as hadchetman_sn,
        
        CASE
            WHEN b.is_status = 1 THEN 0
            WHEN b.is_status = 2 THEN 20
            WHEN b.is_status = 3 THEN 10
        end 
            AS hadchetman_state,
    
        b.add_time as time_create
    
        
        
    
    from dl_member a
        left JOIN dl_member_attest b ON a.id = b.member_id
        INNER JOIN dl_game_type c ON b.game_level = c.id
    
    limit 0,10

    多个left join

    SELECT 
    
        if(a.pay_status =1,null,from_unixtime(a.add_time)) as time_publish_user_pay,
    
        if(a.receive_time='',null,from_unixtime(a.receive_time)) as time_receive_user_pay,
        game_area.name as game_area_name,
      last_division.name as last_season_division_name,
      current_division.name as current_division_name,
      target_division.name as target_division_name,
    
        member.mobile as receive_user_name,
        0 as is_delete,
        1 as data_version 
    
    from dl_order a
        LEFT JOIN dl_order_lol b ON b.order_id = a.id
        left JOIN dl_game_type game_area on b.game_area = game_area.id 
      left join dl_game_type last_division  on b.game_start_level=last_division.id
        left join dl_game_type current_division  on b.game_start_level=current_division.id
      left join dl_game_type target_division  on b.game_start_level=target_division.id
        left JOIN dl_member member on a.receive_member_id  = member.id 
      
    
        ORDER BY a.id desc
    
    limit 0,100
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  • 原文地址:https://www.cnblogs.com/wesky/p/6739821.html
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